Changeset 2910

Timestamp:

01/26/10 09:24:07 (15 years ago)

Author:

Mathieu Morlighem

Message:

Added useful comments

Location:

issm/trunk/src/c/Bamgx

Files:

• QuadTree.h (modified) (1 diff)
• objects/Geometry.cpp (modified) (3 diffs)
• objects/QuadTree.cpp (modified) (8 diffs)

issm/trunk/src/c/Bamgx/QuadTree.h

@@ -7 +7 @@
         const int MaxDeep = 30;
         typedef  long  IntQuad;
-        const IntQuad MaxISize = ( 1L << MaxDeep);
+        const IntQuad MaxISize = ( 1L << MaxDeep); //long int 1, bitwise operation: 8L = 00001000 << 2L -> 00100000 shifted left by 2
         class Triangles;
         class Vertex;

issm/trunk/src/c/Bamgx/objects/Geometry.cpp

@@ -504 +504 @@
                 for (i=0;i<nbv;i++) vertices[i].link = vertices+i;
 
-                //build quadtree for this geometry (error if we have duplicates (k>0))
+                //build quadtree for this geometry
                 for (i=0;i<nbv;i++){
 
@@ -515 +515 @@
                         vertices[i].i=toI2(vertices[i].r); 
 
-                        //Build the quadtree:
+                        //find nearest vertex already present in the quadtree (NULL if empty)
                         Vertex* v=quadtree.NearestVertex(vertices[i].i.x,vertices[i].i.y); 
+
+                        //if there is a vertex found that is to close to vertices[i] -> error
                         if( v && Norme1(v->r - vertices[i]) < eps ){
                                 // mama's old trick to get j 
@@ -528 +530 @@
                                 k++;          
                         }
-                        else  quadtree.Add(vertices[i]); //Add vertices[i] to the quadtree
-                }
+
+                        //The nearest vertex was non existent or far enough from vertices[i]
+                        //Add vertices[i] to the quadtree
+                        else  quadtree.Add(vertices[i]);
+                }
+
+                //if k>0, there are some duplicate vertices -> error
                 if (k) {
                         printf("number of distinct vertices= %i, over %i\n",nbv - k,nbv);

issm/trunk/src/c/Bamgx/objects/QuadTree.cpp

@@ -15 +15 @@
 namespace bamg {
 
+        //INTER_SEG(a,b,x,y) returns 1 if [x y] is included in [a b]
 #define INTER_SEG(a,b,x,y) (((y) > (a)) && ((x) <(b)))
+        //ABS(i) retruns |i|
 #define ABS(i) ((i)<0 ?-(i) :(i))
+        //MAX1(i,j) returns max(i,j)
 #define MAX1(i,j) ((i)>(j) ?(i) :(j))
+        //NORM(i1,j1,i2,j2) returns max(|i1-j1|,|i2-j2|)
 #define NORM(i1,j1,i2,j2) MAX1(ABS((i1)-(j1)),ABS((i2)-(j2)))
-
+        //IJ(i,j,l) returns 3 if (1,1,1), 2 if (0,1,1), 1 if (1,0,1), else 0
 #define IJ(i,j,l) ( ( j & l) ? (( i & l) ? 3 : 2 ) :( ( i & l)? 1 : 0 ))
+        //I_IJ(k,l) retruns l if first  bit of k is 1, else 0
 #define I_IJ(k,l)  (( k&1) ? l : 0)
+        //J_IJ(k,l) retruns l if second bit of k is 1, else 0
 #define J_IJ(k,l)  (( k&2) ? l : 0)
 
@@ -46 +52 @@
         /*FUNCTION QuadTree::QuadTree(){{{1*/
         QuadTree::QuadTree() : 
-                lenStorageQuadTreeBox(100),
-                th(0),
-                NbQuadTreeBox(0),
-                NbVertices(0),
-                NbQuadTreeBoxSearch(0),
-                NbVerticesSearch(0){
-                        sb =new StorageQuadTreeBox(lenStorageQuadTreeBox);
+                lenStorageQuadTreeBox(100), // by default 100 vertices by box
+                th(0),                      // initial mesh = NULL
+                NbQuadTreeBox(0),           // initial number of quadtree boxes = 0
+                NbVertices(0),              // initial number of vertices = 0
+                NbQuadTreeBoxSearch(0),     // initial ?? = 0
+                NbVerticesSearch(0){        // initial ?? = 0
+                        //create lenStorageQuadTreeBox (100) StorageQuadTreeBox elements
+                        sb  =new StorageQuadTreeBox(lenStorageQuadTreeBox); 
+                        //root=QuadTreeBox* pointer roward ??
                         root=NewQuadTreeBox();
                 }
@@ -71 +79 @@
                 pb = &root;
                 while((b=*pb) && (b->n<0)){ 
-                        b->n--;
-                        l >>= 1;
-                        pb = &b->b[IJ(i,j,l)];
+                        b->n--;                //n=n-1 in b->n
+                        l >>= 1;               //shifted righ by one bit: l=00000010 -> 00000001
+                        pb = &b->b[IJ(i,j,l)]; //pointer toward b
                 }
                 if  (b) {      
@@ -81 +89 @@
                         if (b->n > 0 &&  b->v[0] == &w) return;
                 }
+
+                //check that l is still non zero
                 if (l==0){
-                        throw ErrorException(__FUNCT__,exprintf("l==0"));
+                        throw ErrorException(__FUNCT__,exprintf("l==0 cannot be true as it has been initialized as MaxISize = %i",MaxISize));
                 }
                 while ((b= *pb) && (b->n == 4)){ // the QuadTreeBox is full
@@ -121 +131 @@
                 IntQuad  hb=MaxISize;
                 Icoor1   i0=0,j0=0;
+                //iplus= i projected in [0,MaxISize-1] (example: if i<0, i=0)
                 Icoor1   iplus( i<MaxISize?(i<0?0:i):MaxISize-1);
+                //jplus= j projected in [0,MaxISize-1] (example: if j>=MaxISize, j=MaxISize-1)
                 Icoor1   jplus( j<MaxISize?(j<0?0:j):MaxISize-1);
-
-                Vertex *vn=0;
+                //initial nearest vertex pointer
+                Vertex*  vn=NULL;
 
                 //initialization for optimization
@@ -130 +142 @@
                 register Int4 n0;
 
-                if (!root->n) return vn; // empty tree 
-
+                //if the tree is empty, return NULL pointer
+                if (!root->n) return vn; 
+
+                //else: find the index n of the non empty
+                //QuadTreeBox containing  the point (i,j)
                 while( (n0 = b->n) < 0){
-                        // search the non empty 
-                        // QuadTreeBox containing  the point (i,j)
                         register Icoor1 hb2 = hb >> 1 ;
-                        register  int k = IJ(iplus,jplus,hb2);// QuadTreeBox number of size hb2 contening i;j
-                        register QuadTreeBox * b0= b->b[k];
-                        if ( ( b0 == 0) || (b0->n == 0) ) break; // null box or empty   => break            
+                        register  int k = IJ(iplus,jplus,hb2);// QuadTreeBox number of size hb2 containing i;j (Macro)
+                        register QuadTreeBox* b0= b->b[k];
+                        if (( b0 == 0) || (b0->n == 0)) break;// null box or empty   => break       
                         NbQuadTreeBoxSearch++;
                         b=b0;   
-                        i0 += I_IJ(k,hb2); // i orign of QuadTreeBox
+                        i0 += I_IJ(k,hb2); // i orign of QuadTreeBox (macro)
                         j0 += J_IJ(k,hb2); // j orign of QuadTreeBox 
                         hb = hb2; 
                 }
 
+                // if n0>0 ???
                 if ( n0 > 0){  
                         for(register int k=0;k<n0;k++){
@@ -169 +183 @@
                                 register int k = pi[l];
 
-                                if (b->n>0){ // Vertex QuadTreeBox none empty
+                                if (b->n>0){ // Vertex QuadTreeBox not empty
                                         NbVerticesSearch++;
                                         I2 i2 =  b->v[k]->i;
@@ -179 +193 @@
                                           }
                                 }
-                                else{ // Pointer QuadTreeBox 
+                                else{ // Pointer QuadTreeBox
                                         register QuadTreeBox *b0=b;
                                         NbQuadTreeBoxSearch++;